January 18, 2022

Scientific assessment focuses on Illinois climate

CHICAGO — A first Illinois-specific assessment on the predicted effects of climate change on agriculture, hydrology, human health and native ecosystems was released April 20 by The Nature Conservancy.

The report is the culmination of in-depth analysis co-led by Donald Wuebbles, University of Illinois professor of atmospheric science; Jim Angel, who served as Illinois state climatologist for 34 years; Karen Petersen, The Nature Conservancy climate change project manager; and Maria Lemke, The Nature Conservancy director of conservation science; along with 41 contributing scientists from universities and U.S. agencies.

“Our goal for this assessment was to analyze the peer-reviewed literature and to assess the state of the knowledge regarding the current and projected impacts of climate change in Illinois,” Wuebbles said.

“Illinois is already experiencing societal impacts to changing climate, and as climate change progresses and temperatures continue to rise, the impacts are expected to increase over time. The report paints a stark picture of the changes in store for Illinois as a result of our changing climate.

“Climate change is a lot more than just temperature change. It really is about extreme weather, and that’s what really has an impact on humanity.”

“It really is about extreme weather, and that’s what really has an impact on humanity.”

—  Donald Wuebbles, University of Illinois professor of atmospheric science

“Agriculture is the central pillar of our economy, and it’s a dominant part of the landscape. So, Illinois’ fertile soils, level to gently sloping land and the favorable climate make it uniquely qualified to be the major agriculture producer in the Midwest, especially with corn and soybeans,” Angel said.

“Yet, the favorable climate that Illinois farmers depend on is already and will continue to be impacted by climate change. When you talk to farmers, they’re well aware of the impacts of climate change that are already occurring at the farm level for many years now.

“Farmers are already affected by trends toward the overall weather conditions and in particular heavy rain events that are causing flooding, soil erosion and nutrient losses. And the other shoe to drop is the impact of the much warmer temperatures expected by the mid to late century.”


The comprehensive report found that:

• The average daily temperature has increased by 1 degree to 2 degrees in most areas, and nighttime temperatures have risen about three times the rate of daytime temperatures over the past 120 years.

• Precipitation has increased 5% to 20%, varying across the state, and the number of days with at least 2 inches of rain has increased by 40% over the past 120 years.

• By the end of the century, unprecedented warming of 4 degrees to 14 degrees is likely, depending on overall greenhouse gas emissions levels, accompanied by large increases in extremely high temperatures, more intense storms and notably higher annual precipitation totals.

• By 2050, Illinois could see an increase of 40 to 55 days each year where the daily temperature exceeds 86 degrees, which triggers heat stress in numerous livestock species.

• By the end of the century, total annual precipitation is projected to increase by 2% to 10%.

• Hotter summer temperatures will mean longer, more severe droughts.

• Flooding from streams and rivers has increased and likely will become more common, particularly on the Mississippi and Illinois rivers.

• Higher temperatures and increased precipitation are likely to reduce soil organic matter, affecting the fertility and water-holding capacity of Illinois soils.

• Increased intensity of precipitation events is likely to lead to increased erosion if soils are not protected.

• Heat and water stress are likely to reduce corn yields by mid-century, depending on investments made today in agricultural technology and adaptive management, and livestock will face growing threats related to heat, reduced forage quality and increased disease.

• Warmer temperatures will make certain fruits, vegetables and nuts unable to thrive in Illinois, while expanding ranges for others.

• Weeds, pests and diseases are expected to worsen because of warmer winters, increased spring precipitation and higher temperatures.

“Illinois farmers are used to dealing with changes in the weather, but climate change will bring more extreme variability and create new risks for the agricultural sector,” Lemke said.

“The findings in this report highlight the need to develop creative solutions that can help reduce those risks. Many strategies already exist that farmers can use to adapt to future changes.”


For instance, the agricultural sector can increase investment in research, technology and adaptive management solutions now to build resilience to the impacts of climate change.

Farmers can implement in-field and edge-of-field practices to improve soil health, increase water retention and reduce erosion and runoff.

Farmers can also take important steps to reduce their own emissions by improving on-farm energy efficiency, adopting cover crops and reducing fertilizer use, among other actions.

While existing knowledge on the impacts of climate change in Illinois provides an excellent foundation and a clear call to action, additional research would be beneficial to further refine the projections:

Agriculture: Research is needed to better understand how plants will respond to new stresses, such as higher carbon dioxide levels and longer droughts, under different management practices. It would also be helpful to further explore the impact of climate change on insects, microorganisms and weeds, both helpful and harmful, and to improve data on the soil carbon sequestration potential of conservation agricultural practices. Social science research is needed to improve our understanding of the vulnerability of rural communities, strategies to enhance adaptive capacity and resilience, and barriers to adoption of new strategies.

Improved climate modeling: Higher-resolution models would provide more robust simulations of heat waves, severe thunderstorms and extreme precipitation.

Water resources and flooding: Managing drinking and irrigation water supplies is critical in a changing climate, and large-scale water projects take a long time to build. Strategies to combine conventional water infrastructure with green infrastructure could ease flooding risks.

Human health: Social science research is critical to improve understanding of the vulnerability of rural and urban communities; develop strategies to help people adapt to a changing climate and improve adoption of health communication strategies. The relationship between climate change and mental health is a burgeoning field of research that needs continued support.

Ecosystems: Research is needed on how plants and animals cope with heavier precipitation and higher temperatures, to inform natural resource management decisions. In particular, studies are needed to improve ecosystem restoration efforts, which can help lessen the effects of climate change.

“What we found was that in Illinois there is rapid change already happening in weather patterns that are transforming our entire state from cities to our rural communities and is likely to affect all aspects of life in Illinois, including human health, farming and the economy,” said Michelle Carr, The Nature Conservancy in Illinois director.

“Most importantly, the assessment reveals how this crisis in Illinois is critical, but how decisive actions and policies can still prevent our state from forever being altered and that is if we act now.”

Tom Doran

Tom Doran

Field Editor